Operation Manual for - Mrclab.com

Ultrasonic milk analyzerAPPENDIX 3 MILK SAMPLING AND PREPARATION OFSAMPLES FOR ANALYSES1. GeneralMilk sampling and qualification of raw, thermally treated milk and itsderivatives (cream, whey, buttermilk etc.) is accomplished for every separatehomogeneous batch. As homogeneous batch is accepted:• Milk, delivered by a separate producer (an individual farm, farm etc.),and received from one kind of animals after their complete milking,independently from the number of milk-cans and tanks.• Milk, received from one or several farms or milk collecting centers, butdelivered in a joint vessel.• In the enterprise – from one and the same kind raw milk poured in onevessel.• For cream, whey, buttermilk etc. – produced as a result of milkprocessing and its derivatives from one and the same kind and quality,poured in a separate vessel.Milk is qualified not earlier than 2 hours after milking.When the milk is frozen it has to be warmed up to 10-15 o С and stirredaccording the below-described procedure.A sample is taken from every separate vessel proportionally to the quantity ofthe milk in it. Samples from the different vessels are mixed well and from thereceived medial sample are taken 200 - 250 cm 3 for accomplishing theneeded analyses.2. Stirring the milk and its derivatives before samplingMilk stirringIt is a very important condition for receiving exact results. Before takingsamples from big vessels the milk (fresh or thermally treated, whole-milk orwhipped) has to be well stirred for no less than 5 min., by vertical and circularslow movements. Mixing spoon with long handle is used, allowing the lowestlayers of the liquid to be reached.The milk in the milk-cans is stirred 5 to 8 times from the surface to the bottomand reverse with slow circular movements.Cream stirringDue to the fact that the cream is significantly thicker liquid than the milk andcontains high percentage fat it has to be preliminary very well stirred from thesurface to the bottom with reciprocation movements at about 20-25 times.Whey and buttermilk stirringIt is analogical to milk stirring.Operation manual 62/98